Soybean growers who planted seed treated with ILeVO this spring saw an interesting visual event. Soybean seedlings emerged from the ground light-green in color. But, as cotyledons were exposed to sunlight, the edges began to turn yellow and then brown. At first you may think this discoloration indicates the crop is failing. But within days growers found stronger, more robust plants as a result of ILeVO.
This temporary visual event is called the "halo effect" and its appearance is visual proof that ILeVO seed treatment is working to protect soybeans from major yield-robbing threats including Sudden Death Syndrome and soybean nematodes, say researchers at Bayer CropScience.
The majority of plants treated with ILeVO will experience the halo effect to varying degrees. Early signs of the halo effect include discoloration on the edge of the cotyledons, which remains present until they fall off. The discoloration is triggered by ILeVO seed treatment absorbed into cotyledons after systemic movement. The color change doesn't appear on the true leaves of the plant and doesn't harm the interior tissue of the cotyledons, the scientists say.
New ILeVO seed treatment doesn't harm soybean plants
For rapidly growing plants, the halo effect may be hard to see. But even in the absence of visual symptoms, the efficacy on the root rot phase provides a yield benefit, according to Bayer researchers.
Bayer saw the halo effect throughout four years of product research and found it doesn't harm the plant or impact ILeVO's efficacy of SDS control or its yield benefits. University studies found similar results. Joint research by Iowa State and Purdue concludes "if fields that have a history of SDS and were or will be planted under less than ideal conditions, inclusion of ILeVO in the seed treatment package may be a benefit that outweighs the short-term injury to seedlings in the cotyledon stage."
Bayer studies in 2013 and 2014 showed no interaction with preemergence herbicides. Both Bayer and university agronomists conducted field and greenhouse trials to identify any potential herbicide interactions. Testing continues in 2015.
SDS is an increasing soybean disease threat in Iowa, Midwest
The threat of SDS is real and on the rise, says ISU Extension plant pathologist Daren Mueller. It's estimated since 2009, SDS has contributed to an annual yield loss of more than $500 million and continues to expand across state lines. Initial infections of SDS occur on roots and crowns of young soybean plants as early as the seedling stage. This early infection causes a root rot phase that impacts the early season health of soybean seedlings.
Likewise, soybean cyst nematode is also a major threat. SCN contributes to the largest loss of revenue for soybean growers in the U.S. Over the past five years, SCN has caused an average loss of 126 million bushels a year. If both SDS and SCN are present in a field, the impact on yield can be more severe than if only one is present, says Mueller. Knowing and leveraging the tools available is essential to protecting soybean crops from these yield-robbing pests.
First and only seed treatment for SDS and SCN activity
ILeVO is the first and only seed treatment for SDS and SCN activity on the market today. Bayer says ILeVO is unique because it protects the root system in the early growth stages, making plants healthier from the start. Combining ILeVO with Poncho/VOTiVO provides control of nematodes, insects and the SDS fungus. When foliar SDS symptoms are present, the company says you can expect a 4 to 10 bushel per acre increase using ILeVO and Poncho/VOTiVO.
To learn more about the halo effect and how ILeVO can help soybean plants, visit bayercropscience.us.